There has been a heightened focus on efforts to purge people from voter rolls since the 2016 election, on both sides of the aisle. Democrats have redoubled their efforts to strengthen voter protections, recognizing that constraints on voting disproportionately affect younger voters, poorer voters and nonwhite voters, important parts of the party’s base. Republicans have argued for more aggressive policing of who’s registered to vote, often echoing President Trump’s claims that, for example, keeping dead people on the voter rolls contributes to widespread voter fraud.

But there is no widespread voter fraud. There are, however, efforts to limit the ability to vote specifically to affect the electoral chances of the Democrats. There are also laws aimed at culling the voter rolls that have the effect of disenfranchising Democratic voters even if that may not be the intent. From a legal perspective, the difference between the latter two is important.

On Monday, the Supreme Court ruled that Ohio’s aggressive voter-roll-trimming process could continue. In that state, voters missing a federal election are sent a notice asking them to confirm their residence. If they don’t reply and then fail to vote over the next four years, they are removed from the list of eligible voters.

That seems fair, on its surface. The effect, though, is to remove less frequent voters from the voter rolls, people who might only learn that their registration has lapsed on going to the polls. In effect, it can add a layer of bureaucracy that discourages people — people who already don’t vote regularly — from voting. And, in effect, it has more of an impact on Democrats than Republicans.

Let’s consider this on a national level. The political data and consulting firm L2 maintains a database of voters nationally, which we used to determine how an Ohio-style policy would affect registration across the United States.

In this case, we looked at the data on voters who missed the 2012 election and then failed to vote in 2014 and 2016 as well. There are some asterisks: They would also have to have failed to respond to that mailed notice, for example, and a vote cast in 2013, say, would reset the clock. But if we simply want to understand how this affects members of each party, the presented scenario should work.

According to L2 data, just under 40 percent of active voters nationally are Democrats, compared with about 33 percent who are Republicans. Among those who missed the past three federal elections, though, about 36 percent are Democrats and 18 percent Republicans. (The plurality are what L2 codes as “nonpartisan,” which can mean different things in different states.)

One big factor here is residential transience. Among all voters, about 56 percent are identified as likely homeowners in L2’s data, with about 26 percent identified as renters. Among those who missed the last three elections, about 39 percent are likely homeowners and 34 percent are likely renters. Renters are more likely to move, of course — but they’re also more likely to have lower incomes that can correlate to lower turnout rates (thanks to factors like unusual work hours).

Consider the largest state in the nation. Democrats are the largest political group in the state while non-partisans are the biggest group among those who’ve missed the past three elections, though only by a hair. But the change among the densities of the two major parties between the overall registration and those who’ve missed recent elections is lopsided: About 16.3 percent of Democrats missed the past three federal general elections while about 12.6 percent of Republicans in the state did.

Nationally, about 17.6 percent of Democrats missed the past three elections, compared with about 10.3 percent of Republicans.

Paul Mitchell, of the California-based data firm Political Data, broke out the numbers in the state even further. Three-in-10 of those who missed the past three elections are Latino, compared with a quarter of the state overall. Nearly half, 47 percent, live in Los Angeles County.

Democrats outnumber Republicans in most large states, but they often vote less frequently. The upshot is that both nationally and in the 10 largest states in the country, the ratio of Democrats to Republicans is larger among those at risk of being purged by an Ohio-style rule than among the overall voting pool.

By actively purging infrequent voters from voter rolls, the effect in each of these states would be to affect Democrats more than Republicans. Some of those purged did move and don’t need their registrations. But some will have been purged because they, like the voter at the center of the Supreme Court case, simply missed a presidential election and didn’t vote in midterms. To vote again, they would need to re-register to vote, whether or not they’re aware of it.

That additional step would affect more Democrats than Republicans — like the 6 million more Democrats than Republicans who didn’t vote in 2012, 2014 or 2016.